1. Field of the Invention
The present invention relates to pesticidal compounds and compositions based on phosphorous acid and mono-ester derivatives and especially salts thereof for new and surprisingly unexpected methods of use to control arthropod pests, including insects and arachnids. In particular, it pertains to the application to a locus, especially to plants or the habitat thereof, of said compounds or compositions thereof in agriculture, horticulture, etc. as pesticides, without causing significant injury to the plants and also with good safety to the user and the environment.
2. Description of the Related Art
It has been well known for more than 10 years to use phosphorous acid, its salts and salts of some of its monoesters, especially aluminum tris-(O-ethyl phosphonate), fosetyl-Al, commonly known as the commercial product ALIETTE.RTM., as an active ingredient effective against plant fungal diseases. It has been more recently discovered that fosetyl-Al is also unexpectedly active against plant bacterial diseases, which differ significantly from fungal diseases in their causes and especially in their difficulty of control.
Fosetyl-Al has the unique feature of being systemically active in both an upward (xylem) and downward (phloem) direction and has thus enabled new strategies to be used in the control of diseases which affect the above ground as well as below ground portions of plants. Thus foliar applications can advantageously combat root diseases, stem/trunk applications can advantageously combat root diseases as well as foliage or fruit diseases, and root, seed or soil applications can advantageously combat diseases of above ground plant portions.
While these compounds, and especially fosetyl-Al, have been well known to combat fungal and bacterial diseases of plants, they have not heretofore been known to be useful to combat other significantly different pest problems. For example, although fosetyl-Al, as an active ingredient in ALIETTE.RTM., has been used in extensive commercial use around the world as a fungicide treatment, it has not been recognized or suggested to have any significant or practical use against arthropod pests, especially insects. In fact, whether against pest (non-beneficial) or beneficial insects and mites, there has been no observation except essentially no or innocuous activity on arthropods.
These uses and activities of phosphorous acid derivatives, especially fosetyl-Al, are described as follows:
as a fungicide in U.S. Pat. Nos. 4,075,324, 4,139,616 and 4,935,410 and in GB patents 2,137,498 and 2,163,652; PA1 as a fungicide and bactericide in U.S. Pat. Nos. 4,542,023 and 4,382,928; PA1 as a bactericide in AU patent A 72530/87, corresponding to EP 249,566; PA1 as part of a seed treatment fungicide mixture to control fungal diseases and in combination with known insecticides to control thrips and weevils as described in Proc. Brit. Crop Prot. Conf. Pests Dis, Vol. 3, 965-70, 1984 and ibid, Vol. 3, 1093-1100, 1986; PA1 as one of 7-10 different commercial fungicides for evaluation on the survival and reproduction of fruitfly as described in J. Environ. Sci. Health, B(4), 407-24, 1985 and Acta Oecol., 6(4), 323-330, 1985; PA1 as a fungicidal seed treatment of cotton seeds for evaluation of fungal disease protection and in combination with various known insecticides for evaluation of effects on millipedes as described in Cot. Fib. Trop., 39(3), 95-97, 1984; and PA1 as a fungicide for its potentially harmful environmental effects on beneficial arthropods (predator mites and honey bees) as described in Phytoma-Defense Des Cultures, No 346, pages 48-49, 1983. PA1 M is a hydrogen atom (when R is a hydroxyl radical) or an alkali metal, alkaline earth metal or aluminum cation; and PA1 n is an integer from 1 to 3.